Cam followers of the pre-cited type are well known in the technical field and are used, for example, in V-type engines with a central camshaft for transmitting the cam lift to corresponding tappet push rods. These cam followers comprise a hydraulic clearance compensation element that communicates with the oil supply gallery of the internal combustion engine. In recent times, such cam followers are also being increasingly designed for being connected to or disconnected from the cam lift.
A supply of hydraulic medium to the pressure piston that is axially displaceable in the housing is effected through a duct from the internal combustion engine extending radially through the housing into the reservoir. The reservoir thus serves to store the hydraulic medium for supply to the hydraulic clearance compensation device. On the upper side of this reservoir is arranged an axial passage for further conveyance of the hydraulic medium towards or through the tappet push rod. It is also possible, in this way, to lubricate other valve train components like the support of the tappet push rod or contact points on the rocker arm etc. If necessary, provision can also be made for the supply of switching oil to a switching mechanism in the rocker arm.
As disclosed, for instance, in FIG. 9 of U.S. 2003/0075129 A1, the supply pressure of the hydraulic medium in the reservoir acts without being throttled in the direction of the axial passage of the support for the push rod. Under certain circumstances, an excessive loss of hydraulic medium can occur in this arrangement during the firing of the internal combustion engine and this can lead to a deficient supply of hydraulic medium to the clearance compensation device. In other words, an unnecessarily high diversion of the hydraulic medium flow takes place in the direction of the tappet push rod.
In addition, it is noticed that the aforesaid prior art has the inherent danger of a “choking” of the axial passage due to impurities contained in the hydraulic medium or primary dirt particles in the internal combustion engine etc. Thus, the lubricating function through the axial passage would be obstructed and this could cause damage to the friction surfaces to be lubricated.